Trying to complete an assignment by masking out a roof in with blue sky and replacing it with a jpg image, but when I create the mask and go to set the mask mode, there is no menu like there is in the diagram in our textbook (Adobe After Effects CC 2014 release Classroom in a Book). I have attached a screenshot of where I'm stuck at on the After Effects software. Any help is much appreciated!

you have possibly hidden columns or you are working in the Ray-traced rendering mode, or you need to learn how to use the little timeline icons at the bottom left corner of the time line. It's impossible for me to tell exactly what's going on without a screenshot of your whole project. You can just snap a screenshot and drag it right into the reply field on this forum.